Does Menstruation Make Women Hungry?

Agence Science-Presse

In addition to the symptoms commonly associated with menstruation — cramps, bloating, headaches, fatigue — many women report increased hunger. Does the body truly have this extra need for energy, or should hormones be blamed? This is the question posed by the Organization for Science and Society and the Rumor Detector.

One way to find out is to calculate what is called the basal metabolic rate (BMR). This is the amount of energy our body expends at rest.

It can be measured in many ways, but the most common is the amount of oxygen a person inhales or the amount of carbon dioxide they exhale at rest. Using the Weir formula, we can deduce the number of kilocalories our body burns per day at rest.

If menstruation were causing increased energy demands, this should be reflected in these women’s BMRs during that period.

Easier to Destroy

It turns out that the BMR during menstruation decreases during the bleeding period. This basal metabolic rate reaches its lowest point one week after the start of menstruation, before steadily increasing until the start of the next period. This curve appears to correspond to the variations in the thickness of the uterine lining throughout the cycle.

While menstruation is, from the perspective of the person experiencing it, the most difficult part of the menstrual cycle, it is actually the easiest part for the body. The uterus takes three weeks to build an inner lining approximately 11 millimeters thick, complete with glands and blood vessels, which is no small feat. Shedding it during menstruation is much simpler.

For the body, the most energy-intensive portion of the menstrual cycle is therefore the period from days 8 to 28, during which the body builds tissue, and not days 1 to 7, when this tissue is broken down and shed. However, the uterus is not completely inactive. It contracts throughout the menstrual cycle, but particularly strongly during bleeding.

The question remains: if it’s not caused by an increased metabolic rate, why do we feel hungry just before or during our period?

The blame lies (in part) with hormones. As early as 2012, research established that progestins, such as progesterone, can stimulate appetite. Levels of this hormone peak about a week before the start of menstruation, which helps explain the hunger pangs in the days leading up to menstruation.

Similarly, although the BMR decreases during menstruation, it is at its highest just before. Researchers have estimated that this rate varies by about 8% during the menstrual cycle, or 164 calories. That’s the equivalent of three-quarters of a chocolate bar, or about one and a half oranges. Nothing massive, but enough to impact hunger before your period.

However, bodily changes can’t be blamed entirely. Eating is comforting: when you’re dealing with painful cramps or even emotional distress, comfort foods become especially helpful.

Verdict: While you might feel hungry just before or during your period, it’s not essential to consume more calories. There is a slight increase in calorie needs during the two weeks leading up to menstruation, but it’s small enough to fall within the normal fluctuations of a diet.